Certain silane compounds, including some amine-containing silane compounds, are said to be useful for attaching organic groups to mineral fillers; see "Silane treatment of mineral fillers--practical aspects", by E. J. Sadler, Plastics, Rubber and Composites Processing and Applications Vol. 24, No. 5, 1995, pages 271 to 275.
It is known to prepare some N-substituted-3-(trialkoxysilyl)propylamines by reacting a 3-chloropropyltrialkoxysilane with a primary amine or reacting an alkyl chloride with a 3-aminopropyltrialkoxysilane, at reflux in an alcoholic solution, where the alcohol solvent corresponds to the alkyl group of the alkoxy portion of the silane. This is largely unsatisfactory as the alcohols CH.sub.3 OH, C.sub.2 H.sub.5 OH and C.sub.3 H.sub.7 OH boil at temperatures below 98.degree. C., which is lower than the temperature required to obtain good yields of the desired products in a reasonable time. While higher boiling alcohols, for example butanol, may be used to achieve higher reflux temperatures and hence increased reaction rates, this can result in an exchange of alkoxy groups of the alcohol with those of the silane and a much decreased yield of the desired producl The reaction rates can be increased by using higher temperatures and a pressure autoclave, but this still requires removal of the solvent alcohol, which complicates the synthesis, and also requires specialized equipment (autoclave), which is undesirable.
It is also known to prepare some N-substituted-3(trialkoxysilyl)propylamines by reacting 3-bromopropyltrialkoxysilane with a primary amine, or reacting an alkyl bromide with a 3-aminopropyltrialkoxysilane at reflux in alcohol solution. Again, it is desirable that the alkoxy group of the alcohol is the same as the alkoxy group of the silane. While in some cases satisfactory yields can be obtained, in others the temperature of the boiling solvent is too high, causing unwanted side reactions, for instance dehydrobromination of the starting 3-bromopropyltrialkoxysilane. In any case, it is necessary to remove the alcohol to obtain the required product, which is expensive and disadvantageous, particularly if it is important to remove all traces of the solvents.